In accordance with the International Telecommunication Union E.170 relating to telephone network and ISDN operation, numbering, routing, and mobile service, the objective of telecommunications "routing" is to establish a successful connection between any two exchanges in the telecommunications network. More broadly, the function of traffic routing is the selection of one or more particular circuit groups or routes for a given call attempt to establish a call connection via the network.
A telecommunications network comprises a number of nodes or switching points interconnected by circuit groups. An example of a switching point is a telephone exchange. A telephone subscriber looking into the telecommunications network is served by a local exchange. Within a national network, there is typically a hierarchy of switching centers including for example local, trunk, regional, and international with each level performing different functions. Physical communications media connecting one switching point or exchange with another are often referred to as "trunks," and physical communications media connecting a subscriber to the local exchange that serves the subscriber are often referred to as "lines." There may be several direct connections, e.g., trunks, between a pair of nodes which can be either unidirectional or bi-directional. A circuit group includes all of the direct connections between two nodes. A route is defined as one or more circuit groups providing a connection between switching points or other network nodes.
A routing scheme in the network defines how a set of routes is made available for calls between a pair of nodes. The routing "scheme" may be direct or indirect, fixed or dynamic. A direct route connects two nodes by a single circuit group without any intermediate nodes. An indirect route is a series of circuit groups connecting two nodes provided in end-to-end connection via other nodes. For a fixed routing scheme, the set of routes in the routing, pattern is always the same. In the case of a dynamic routing scheme, the set of routes in the routine pattern varies. The route selected for a specific call may be sequential or non-sequential. In sequential selection, routes in a set are always tested in sequence, and the first available route is selected. For non-sequential selection, the routes are tested in no specific order.
Call control procedures in the network define the entire set of interactive signals necessary to establish, maintain, and release the connection between exchanges. In originating call control, the originating exchange maintains control of the call setup until the connection between the originating and terminating exchanges is completed. Progressive call control uses link-by-link signaling to pass supervisory controls sequentially from one exchange to the next. Call control is "reversible" when that control signaling can be passed "backwards" using automatic rerouting or "crank back" actions. Accordingly, if a congestion signal is received from one downstream exchange subsequent to the seizure of an outgoing circuit from the originating exchange, the call is rerouted at the originating exchange.
Routing schemes generally attempt to share the traffic load among routes. Traffic is defined generally as a process of events related to demands to use resources in a telecommunications network. The most commonly recognized traffic example is telephone calls. More specifically, routing schemes may be developed to ensure that call attempts are offered to certain preselected routes according to a preplanned distribution. Consider for example an incoming traffic stream to a switching point or node having a particular destination, e.g., the same area code. The switching node might have four outgoing routing patterns A, B, C, and D to that particular destination with each routing pattern including one or more routing options. In accordance with the preplanned distribution, each routing pattern may be preset to receive a certain ratio or percentage of the total number of outgoing calls.
However, distributing call attempts to a particular destination in a fixed ratio between the specified outgoing routing pattern can be problematic. Consider for example the situation where a country or other geographic region is served by more than one telecommunications carrier or network operator. Each outside carrier that supplies traffic to that country or region desires that other carriers inside that country or region return to it a "fair" amount of traffic. One example definition of "fair" is each carrier receives as outgoing traffic from the node substantially the same percentage of total node traffic that carrier supplies as incoming traffic to the node.
Even though traffic patterns at a particular switching point often change, fixed load share routing schemes do not account for such changes and therefore generally fail to return fair amounts of traffic. One solution to ameliorate this problem is to orchestrate payments between various carriers to compensate for distribution inequities, but this solution is difficult to monitor and costly to administrate.
A much better solution provided by the present invention is to dynamically distribute traffic in a switching point or node based on the current input traffic pattern at that node. Following the example above, if the four telecommunications operators A, B, C, D are operating in a switching point, the percentage of the total outgoing traffic routed to their respective carrier routes routing patterns A2, B2, C2, and D2 should be approximately the same as the traffic percentage received on corresponding incoming carrier routes A1, B1, C1, and D1.
It is therefore an object of the present invention to achieve dynamic traffic distribution at a switching point or other network node.
It is a further object of the present invention to ensure that different routes, groups of routes, carriers, operators, etc. connected to a switching point or other network node receive a fair share of traffic.
It is a further object of the present invention to minimize the cost and administration required to ensure that such different routes, groups of routes, carriers, operators, etc. receive their fair share of traffic at a particular switching point.
It is a further object of the present invention to provide network operators with a flexible and easy method to define traffic distribution patterns.
The distribution of traffic for incoming carriers to a switching point or other network node and for outgoing carriers from the node may be based on the amount of traffic currently being carried by each network operator/carrier. The amount of traffic may be measured in a variety of different ways such as percentage of total calls per unit time, number of call minutes or seconds over a particular time period or a preset number of calls, etc. Traffic is then redistributed among outgoing carriers based on the traffic distribution detected for corresponding incoming carriers. Such traffic rerouting among the outgoing carriers ensures that each carrier gets its fair share of outgoing traffic from the node based on the amount of traffic it brings to that node.
To implement dynamic traffic distribution at a switching point or other network node, incoming and outgoing traffic controllers detect the amount of traffic coming into and leaving the switching point for each of plural groups of communication routes through the switching point. The incoming traffic controller provides a traffic analyzer with the amount of traffic entering the switching point on each route, group of routes, carrier, etc. and the outgoing traffic controller provides the traffic analyzer with the amount of traffic leaving the switching point on each route, group of routes, carrier, etc.. The traffic analyzer then determines a new output traffic distribution based on the amounts of incoming and outgoing traffic on each route, group of routes, carrier, etc. The traffic analyzer sends a new traffic distribution message to a traffic router, and the traffic router changes the amount of outgoing traffic distributed to each outgoing route. In this way, each outgoing route, group of routes, carrier, etc. may be allocated a fair share of traffic based on the amount of incoming traffic on the corresponding incoming route, group of routes, carrier, etc. Moreover, the difficulties and costs associated with making monetary payments to various operators or carriers as a result of unfair distributions of calls are avoided.
Other features, advantages, and objects of the present invention will be evident from the following detailed description of the invention which provides an example and non-restrictive illustration of how the present invention may be implemented.